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Name

XGetVisualInfo, XMatchVisualInfo, XVisualIDFromVisual, XVisualInfo - obtain visual information and visual structure

Syntax

XVisualInfo *XGetVisualInfo(Display *display, long
vinfo_mask, XVisualInfo *vinfo_template, int *nitems_return);
Status XMatchVisualInfo(Display *display, int screen, int
depth, int class, XVisualInfo *vinfo_return);
VisualID XVisualIDFromVisual(Visual *visual);

Arguments

class
Specifies the class of the screen.
depth
Specifies the depth of the screen.
display
Specifies the connection to the X server.
nitems_return
Returns the number of matching visual structures.
screen
Specifies the screen.
visual
Specifies the visual type.
vinfo_mask
Specifies the visual mask value.
vinfo_return
Returns the matched visual information.
vinfo_template
Specifies the visual attributes that are to be used in matching the visual structures.

Description

The XGetVisualInfo function returns a list of visual structures that have attributes equal to the attributes specified by vinfo_template. If no visual structures match the template using the specified vinfo_mask, XGetVisualInfo returns a NULL. To free the data returned by this function, use XFree.

The XMatchVisualInfo function returns the visual information for a visual that matches the specified depth and class for a screen. Because multiple visuals that match the specified depth and class can exist, the exact visual chosen is undefined. If a visual is found, XMatchVisualInfo returns nonzero and the information on the visual to vinfo_return. Otherwise, when a visual is not found, XMatchVisualInfo returns zero.

The XVisualIDFromVisual function returns the visual ID for the specified visual type.

Structures

The XVisualInfo structure contains:

/* Visual information mask bits */ VisualNoMaskVisualIDMaskVisualScreenMaskVisualDepthMaskVisualClassMaskVisualRedMaskMaskVisualGreenMaskMaskVisualBlueMaskMaskVisualColormapSizeMaskVisualBitsPerRGBMaskVisualAllMask
#define
T}    T{
0x0
T}
#define
T}    T{
0x1
T}
#define
T}    T{
0x2
T}
#define
T}    T{
0x4
T}
#define
T}    T{
0x8
T}
#define
T}    T{
0x10
T}
#define
T}    T{
0x20
T}
#define
T}    T{
0x40
T}
#define
T}    T{
0x80
T}
#define
T}    T{
0x100
T}
#define
T}    T{
0x1FF
T}

0
0>=40 .vs 0u
0<=39 .vs 0p
/* Values */
typedef struct {
    Visual *visual;
    VisualID visualid;
    int screen;
    unsigned int depth;
    int class;
    unsigned long red_mask;
    unsigned long green_mask;
    unsigned long blue_mask;
    int colormap_size;
    int bits_per_rgb;
} XVisualInfo;

See Also

XFree(3X11)
Xlib - C Language X Interface

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